Tracking teeth movement correction

ABSTRACT

Embodiments are provided for tracking teeth movement correction. One method embodiment includes using a set of positioning appliances shaped to move teeth through a number of successive stages of arrangements of an expected teeth arrangement model where each stage corresponds to a particular positioning appliance, mapping a current teeth position based upon positions of a number of physical markers attached to a number of physical teeth, comparing the positions of the number of physical markers with a corresponding number of virtual markers positioned on a number of virtual teeth of a stage in the expected teeth arrangement model, determining whether midcourse correction is needed.

PRIORITY INFORMATION

This application is a Continuation of U.S. application Ser. No.11/712,074, filed Feb. 28, 2007, the specification of which isincorporated herein by reference.

BACKGROUND

The present disclosure is related generally to the field oforthodontics. More particularly, the present disclosure is related to adental model system which can be manipulated to model a series of toothconfigurations for a single patient throughout orthodontic treatment.

Many orthodontic treatments involve repositioning misaligned teeth andchanging bite configurations for improved cosmetic appearance and dentalfunction. Repositioning can be accomplished, for example, by applyingcontrolled forces to one or more teeth over a period of time.

Some orthodontic processes use positioning appliances for realigningteeth. Such appliances may utilize a thin shell of material havingresilient properties, referred to as an “aligner” that generallyconforms to a patient's teeth but is slightly out of alignment with theinitial tooth configuration.

Placement of such an appliance over the teeth provides controlled forcesin specific locations to gradually move the teeth into a newconfiguration. Repetition of this process with successive appliancesthat provide progressive configurations eventually move the teeththrough a series of intermediate arrangements to a final desiredarrangement. An example of such a system is described in U.S. Pat. No.5,975,893.

Such systems generally rely on designing and fabricating some, most, orall of the appliances, to be worn by the patient, at the outset oftreatment. In some processes the design of the appliances relies oncomputer modeling of a series of successive tooth arrangements and theindividual appliances are designed to be worn over the teeth and toreposition the teeth by using the appliances in a serial order,progressing from a first appliance, through each of the intermediateappliances, to the last appliance.

The set of appliances that is designed and fabricated at the outset ofthe treatment is typically planned to reposition the teeth to a finaldesired arrangement. In some cases, the treatment deviates from theplanned process. Such deviations can arise from for example, poorpatient compliance, or other factors.

The deviations will usually become apparent when the next appliance tobe worn in the set of successive appliances does not fit as expected orupon a checkup by the orthodontist where the orthodontist notices thatprogress is not being made as planned. When a subsequent appliance has apoor fit, it indicates that the tooth arrangement has not progressed tothe desired intermediate stage and that the teeth are not ready for thenext appliance.

When such deviations occur, the response has usually been to restart thealignment process by creating new appliances based upon the currentpositioning of the teeth. In order to accomplish this, the location ofthe teeth has to be re-established and another set of appliances arethen planned and fabricated to bring the teeth from the currentintermediate arrangement to the desired final arrangement, which isusually the same, or close to the same, as the final arrangement thatwas the target of the original set of appliances.

Restarting the process, however, can be inefficient and wasteful. Forexample, in such instances, a number of additional appliances have to befashioned in order to start the process again at a new (intermediate)starting point. Additionally, the remaining appliances from the originalset will usually be discarded, since the treatment plan has beensubstantially redone, in many instances.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a jaw of a subject together with an example of anincremental position adjustment appliance suitable for use withembodiments of the present disclosure.

FIG. 2 illustrates a patient's jaw and provides a general indication ofhow teeth may be moved by the methods and apparatuses of the presentdisclosure.

FIG. 3 illustrates a single tooth from FIG. 2 and defines how toothmovement distances can be determined.

FIG. 4 provides a system for analyzing the positions of various physicalteeth and in creating virtual models thereof that can be used withembodiments of the present disclosure.

DETAILED DESCRIPTION

According to the present disclosure, systems and methods are providedfor tracking teeth movement correction and/or determining a restartposition within a number of stages of incrementally moving teeth using aplurality of discrete appliances, where each appliance successivelymoves one or more of the patient's teeth by relatively small amounts.The tooth movements are those normally associated with orthodontictreatment, including translation in the three orthogonal directionsrelative to a vertical centerline, rotation of the tooth centerline intwo orthodontic directions (“root angulation” and “torque”), as well asrotation about the centerline.

Referring now to FIG. 1, systems according to the present disclosureinclude a plurality of incremental position adjustment appliances. Theappliances are intended to affect incremental repositioning ofindividual teeth in the jaw as described generally above.

The methods of the present disclosure can employ any positioners,retainers, and/or other removable appliances for finishing andmaintaining teeth positions in connection with orthodontic treatment.The systems for use with embodiments of the present disclosure provide aplurality of such appliances intended to be worn by a patientsuccessively in order to achieve the gradual tooth repositioning asdescribed herein.

An appliance 100 can, for example, be fabricated from a polymeric shellhaving a cavity shaped to receive and resiliently reposition teeth fromone teeth arrangement to a successive teeth arrangement. The polymericshell may be designed to fit over a number of, in many instances allteeth, present in the upper or lower jaw 101.

In some situations, certain individual or small sets of the teeth willbe repositioned while others of the teeth will provide a base or anchorregion for holding the repositioning appliance in place as it appliesthe resilient repositioning force against the tooth or teeth to berepositioned. In complex cases, however, many or most of the teeth willbe repositioned at some point during the treatment.

In such cases, one or more of the teeth which are moved can also serveas a base or anchor region for holding the repositioning appliance.Additionally, the gums and/or the palette can serve as an anchor region,thus allowing all or nearly all of the teeth to be repositioned at thesame time. In some cases, however, individual attachments (e.g.,attachment 216 of the embodiment of FIG. 2) may be affixed on one ormore of the teeth with corresponding receptacles or apertures in theappliance 100.

Referring now to FIG. 2, a representative jaw 201 includes sixteen teeth202. The embodiments of the present disclosure are intended to move oneor more of these teeth from an initial tooth arrangement to a finaltooth arrangement.

To understand how the teeth may be moved, an arbitrary centerline (CL)is drawn through one of the teeth 202. With reference to this centerline(CL), the teeth may be moved in the orthogonal directions represented byaxes 204, 206, and 208 (where 204 is the centerline).

The centerline may be rotated about the axes 208 (root angulation) and204 (torque) as indicated by arrows 210 and 212, respectively. In someembodiments, the tooth can be moved in the six degrees of freedom asthey are understood by those of skill in the art. Of course, based uponthe fact that a tooth is fixed in tissue, the freedom to move a tooth inany direction is not limitless.

In determining the current status of the teeth and how their positioncompares to one or more of the available appliances during the treatmentprocess, in some embodiments, the current teeth position can be mappedbased upon positions of a number of physical markers attached to anumber of physical teeth. The physical markers can be any suitablemarker type and can be permanently or temporarily fixed to one or moreof the teeth to be analyzed.

Various examples of suitable physical markers are discussed below inmore detail with respect to FIG. 3. In some embodiments, an attachment,or other dental component, can be used as a physical marker. Forexample, in FIG. 2, the attachment 216, or parts thereof (e.g., acorner, edge, etc), can be used a one or more physical markers.

In embodiments, where the current teeth are mapped, the mapping processcan be accomplished, for example, by taking an image of at least one ofthe number of physical markers. Any suitable image taking device can beutilized including two and three dimensional imaging devices. In suchembodiments, this information can be analyzed by a computing device oncethe information is input into the computing device.

This input can be accomplished by any suitable digital input mechanism.Scanning the image or taking a digital image are such suitablemechanisms for inputting the information.

In various embodiments, the positions of the number of physical markerscan be compared with a corresponding number of virtual markerspositioned on a number of virtual teeth of a stage (i.e., visuallyillustrated as a virtual teeth model) in the expected teeth arrangementmodel. For example, if the markers are applied at the time that theexpected teeth arrangement model is created and the information aboutthose original positions is kept, then the current positions can becompared to the original positions or to later positioning within thearrangement model.

In instances where the markers were not added when the model wascreated, the markers can be applied to the teeth and then theinformation can be compared to a virtual teeth model. This process canbe aided by creating virtual teeth markers to be used for comparison.

In such embodiments, if the virtual and physical markers are positionedin the same places on the one or more teeth being analyzed, then thedifference in position can be more precisely accomplished, in someinstances. For these virtual and/or physical markers, positionalinformation can be used to identify the position of one or more teeth inthe virtual model and/or the physical teeth arrangement and can be usedto determine which appliance may be the best point to restart atreatment process.

As discussed above, an expected teeth model can also include informationabout the set of positioning appliances that have been fabricated for aparticular patient and have been shaped to move teeth through a numberof successive stages of arrangements of an expected teeth arrangementmodel where each stage corresponds to a particular positioning appliancecan be used. In such embodiments, the information about the currentteeth can be compared with the information about the positioningappliances to determine whether midcourse correction is needed. If it isdetermined that midcourse correction is needed, then a determination ofwhich particular positioning appliance would be most suitable forrestarting a treatment process can be made based upon the comparison.

In some embodiments, a method for tracking teeth movement correction canbe accomplished by creating a virtual teeth model that models a numberof physical teeth as virtual teeth, such as on a computing device. Avirtual treatment process (e.g., an expected teeth arrangement model)can be created that includes one or more treatments having a number oforientations of the number of virtual teeth. In many such embodiments,each treatment is provided by a different appliance.

In various embodiments, a number of virtual markers can be oriented onone or more of the number of virtual teeth in the virtual teeth model.In some such embodiments, a corresponding number of physical markers canbe attached on the physical teeth corresponding to the positions of thevirtual markers on the virtual teeth.

In this way, the virtual and physical markers can be compared. Toaccomplish this comparison, in some embodiments, one or more images(e.g., photos, X-rays, etc.) of at least one of the number of physicalreference markers can be taken.

In such embodiments, taking multiple images over a period of time toidentify a pattern of movement and comparing the positions of the numberof physical markers with a corresponding number of virtual markers canbe performed. This can be accomplished, for example, by analyzing themultiple images taken and identifying physical teeth positionalinformation therefrom and then comparing the physical teeth positionalinformation against virtual teeth positional information.

In some embodiments, the position of the physical markers on the imagecan be detected. Such markers can be compared (e.g., matched) with thevirtual teeth model to obtain actual teeth positions relative to thevirtual teeth model. In this way, a determination can be made whether aparticular appliance is suitable for restarting the treatment process.This comparison can also be useful in generally identifying where in thetreatment process a patient is.

This can be useful in comparing the movement of teeth. For example, insome embodiments, periodic subsequent images can be taken to obtain asequence of physical teeth positions. Positional information can be usedwith computer-implemented computational geometry calculations to verifythat a physical teeth movement gained in a previous periodic imagefollows the virtual treatment process.

This information can also be used to see whether a previously fabricatedappliance would be a useful starting point for restarting the treatmentprocess. For instance, if the virtual model includes the virtualconfigurations of the teeth for each appliance, the information can becompared with each particular appliance until a suitable appliance, ifany, is identified that can be used to restart the treatment process.

In some embodiments, the positional information about an actualappliance may have to be provided to the computing device doing thecalculations and comparisons. In such instances, the information can beentered by an individual into the computing device, provided in a filereadable by the computing device, or can be obtained through analysis ofone or more images of the appliance, similar to the methodology usedabove with respect to obtaining positional information about the currentteeth locations.

For example, some embodiments can be designed to usecomputer-implemented computational geometry calculations to detect theposition of the physical markers on an appliance or one or more teeth onan image. In some embodiments, the positional information can beobtained from the shape of the appliance or the shape of a particulartooth or teeth.

In some applications, an advantage of using markers may be that theamount of computing device processing power is less when calculating thelocation of a number of markers rather than portions of or the entiretooth, teeth, and/or appliance. In such embodiments, the ability to useless processing power may allow a patient or orthodontics office to usea computing device, such as a desktop computing device or local server,to do such calculations. Such ability may result in faster analysisand/or change of treatment.

In another example embodiment, a method can include using a set ofpositioning appliances shaped to move teeth through a number ofsuccessive stages of arrangements of an expected teeth arrangement modelwhere each stage corresponds to a particular positioning appliance. Acorresponding number of physical markers can be attached on a number ofphysical teeth as discussed herein, where the positions of the physicalmarkers on the physical teeth correspond to the positions of the virtualmarkers on the virtual teeth. Since the positions of the physicalmarkers and virtual markers correspond, the amounts of processing powerused for analysis may be less than when non-corresponding positions areused.

One or more current teeth positions can be mapped based upon positionsof the number of physical markers attached to the number of physicalteeth. The positions of the number of physical markers can be comparedwith a corresponding number of virtual markers positioned on a number ofvirtual teeth of a stage in the expected teeth arrangement model. Withsuch comparison information, the determination of whether or notmidcourse correction is needed can be made. And, if it is determinedthat midcourse correction is needed, then a determination of whichparticular positioning appliance would be most suitable for restarting atreatment process can be made based upon the comparison.

In various embodiments, a computer readable medium can have instructionsfor causing a device to perform a method. In such embodiments, acomputer readable medium can be any medium that can store computerreadable information thereon. Suitable examples include optically ormagnetically readable forms of media, among others.

Referring now to FIG. 3, the magnitude of any tooth movement achieved bythe methods and systems of the present disclosure can be defined interms of the linear translation of a point P 314 on a tooth 302. Eachpoint P_(i) will undergo a cumulative translation as that tooth is movedin any of the orthogonal or rotational directions defined in FIG. 2.

That is, while the point will usually follow a non-linear path, therewill be a linear distance between any point in the tooth when determinedat any two times during the treatment. Thus, an arbitrary point P₁ mayin fact undergo a true side-to-side translation as indicated by arrowd₁, while a second arbitrary point P₂ may travel along an arcuate path,resulting in a final translation d₂.

In various embodiments, the positions of virtual teeth and physicalteeth can be located and/or tracked based upon such positionalinformation, among other types of information. In some embodiments, thepoints P in FIG. 3 can represent separate physical or virtual markersprovided as point objects, points within one or more line objects,and/or points within one or more shape or symbol objects.

As stated herein, the markers can be temporary or permanent in variousembodiments. For instance, in some embodiments, the physical markers canbe removed. This can be advantageous in some situations. For example,the markers can be removed between the taking of the periodic images.

In this manner, the patient does not have to have the markers on theirteeth except for short periods, such as when the images are being taken.For such embodiments, any suitable type of removable affixationmechanism can be used to place and remove the markers (e.g., removableadhesives, removable marker materials, marker materials that dissolve orchange color, etc.)

With regard to the types of items that can be used as markers, invarious embodiments, the marker can be an attachment or piece of dentalwork (e.g., filling crown, etc.) that has been applied to a tooth forother orthodontic purpose as, for example, discussed above. In someembodiments, markers are applied that do not serve another purpose maybe provided. The markers, for example, can be dental materials, such asdental fillers or adhesives that are being used as markers and not fortheir typical purpose. In some embodiments, one or more markers can beapplied by a type of writing instrument (e.g., a pen or pencil).

In some embodiments, a medically safe material can be used. This can beadvantageous in some instances, such as when a marker is to be left inthe patient for an extended period.

In various embodiments, markers can include a colorant that istemporarily or permanently visible to the unaided human eye. Forexample, in some embodiments, one or more physical markers can beprovided in the form of a colorant that changes color when the colorantinteracts with a catalyst. Such concepts are discussed in more detailbelow.

Markers can be of any suitable shape. For example, one or more lines(e.g., a line object) can be used which can indicate movement whentracked over time. Symbols and/or shapes (e.g., a shape object), such asa square, triangle, or other shape or symbol can be used for similarpurposes.

Further, one or more dots (i.e., point objects) can be used. Forexample, the use of more than one point can allow for more accuratepositioning than a single point, in some instances. The embodiment in

FIG. 3, for instance, illustrates a number of points that can be used asmarkers. In some embodiments, the use of three or more point objects canbe used which can allow for easier triangulation of a position of one ormore teeth.

Some markers can be placed in positions or sized such that they areinvisible or nearly invisible to the unaided human eye unless the teethare closely examined. For example, a number of small dots may be nearlyinvisible except upon close examination.

In some embodiments, the marker material may be visible outside thevisible range of the human eye. For instance, the material can beradiopaque such that it is viewable in the X-ray spectral range. Thus,in such embodiments, the material may be invisible to the unaided humaneye, but visible in the X-ray spectral range.

Some materials may be visible when exposed to a catalyst. For example,materials that change their visible nature when exposed to chemicals,temperature, or different types of light (e.g., ultraviolet, infrared,polarized, etc.) are such materials. Such embodiments can beadvantageous since the markers can be viewable for purposes of imaging,but may be less visible or not visible prior to and/or after imaging.

FIG. 4 provides a system for analyzing the positions of various physicalteeth and in creating virtual models thereof that can be used withembodiments of the present disclosure. In the system illustrated in FIG.4, the system includes a computing device 418 having a processor 420 andmemory 422. The memory can include various types of informationincluding data 424 and executable instructions 426 as discussed herein.

Additionally, as illustrated in the embodiment of FIG. 4, a system caninclude a network interface 436. Such an interface can allow forprocessing on another networked computing device or such devices can beused to obtain information about the patient or executable instructionsfor use with various embodiments provided herein.

As illustrated in the embodiment of FIG. 4, a system can include one ormore input and/or output interfaces 428. Such interfaces can be used toconnect the computing device with one or more input or output devices.For example, in the embodiment illustrated in FIG. 4, the systemincludes connectivity to a scanning device 430, a camera dock 432, and akeyboard.

Such connectivity allows for the input of image information (e.g.,scanned images or digital pictures, etc.) or instructions (e.g., inputvia keyboard) among other type of information. Although some embodimentsmay be distributed among various computing devices within one or morenetworks, such systems as illustrated in FIG. 4 can be beneficial inallowing for the capture, calculation, and analysis of the variousinformation discussed herein.

Although specific embodiments have been illustrated and describedherein, those of ordinary skill in the art will appreciate that anyarrangement calculated to achieve the same techniques can be substitutedfor the specific embodiments shown. This disclosure is intended to coverany and all adaptations or variations of various embodiments of thedisclosure.

It is to be understood that the use of the terms “a”, “an”, “one ormore”, “a number of”, or “at least one” are all to be interpreted asmeaning one or more of an item is present. Additionally, it is to beunderstood that the above description has been made in an illustrativefashion, and not a restrictive one. Combination of the aboveembodiments, and other embodiments not specifically described hereinwill be apparent to those of skill in the art upon reviewing the abovedescription.

The scope of the various embodiments of the disclosure includes anyother applications in which the above structures and methods are used.Therefore, the scope of various embodiments of the disclosure should bedetermined with reference to the appended claims, along with the fullrange of equivalents to which such claims are entitled.

In the foregoing Detailed Description, various features are groupedtogether in a single embodiment for the purpose of streamlining thedisclosure. This method of disclosure is not to be interpreted asreflecting an intention that the embodiments of the disclosure requiremore features than are expressly recited in each claim.

Rather, as the following claims reflect, inventive subject matter liesin less than all features of a single disclosed embodiment. Thus, thefollowing claims are hereby incorporated into the Detailed Description,with each claim standing on its own as a separate embodiment.

1. A method for tracking teeth movement, the method comprising:receiving a virtual teeth model of physical teeth in an initial tootharrangement using a computing device; positioning at least one virtualmarker on at least one virtual tooth of the virtual teeth model;generating a successive digital tooth arrangement for the virtual teethmodel using the computing device; providing information for positioningat least one physical marker at a location on at least one of thephysical teeth corresponding to a location of the at least one virtualmarker on the at least one virtual tooth; receiving an image of the atleast one physical marker after the physical teeth have moved to asuccessive physical tooth arrangement using the computing device;matching the at least one physical marker at the successive physicaltooth arrangement with the at least one virtual marker at the successivedigital tooth arrangement using computer-implemented computationalgeometry calculations to verify that the successive physical tootharrangement follows the successive digital tooth arrangement using thecomputing device.
 2. The method of claim 1, wherein receiving thevirtual teeth model includes receiving an image of the physical teeth inthe initial tooth arrangement including the at least one physical markerat the location on the at least one of the physical teeth.
 3. The methodof claim 1, wherein receiving the virtual teeth model includes receivingan image of the physical teeth in the initial tooth arrangement withoutthe at least one physical marker at the location on the at least one ofthe physical teeth.
 4. The method of claim 1, where the method includesdetermining a positioning appliance suitable for restarting a treatmentprocess based upon the computer-implemented computational geometrycalculations in response to a determination that midcourse correction isneeded because the successive physical tooth arrangement does not followthe successive digital tooth arrangement.
 5. A non-transitory computerreadable medium, having instructions, which when executed by aprocessor, cause a device to: receive a virtual teeth model of physicalteeth in an initial tooth arrangement using a computing device; positionat least one virtual marker on at least one virtual tooth of the virtualteeth model; generate a successive digital tooth arrangement for thevirtual teeth model using the computing device; provide information forpositioning at least one physical marker at a location on at least oneof the physical teeth corresponding to a location of the at least onevirtual marker on the at least one virtual tooth; receive an image ofthe at least one physical marker after the physical teeth have moved toa successive physical tooth arrangement using the computing device;match the at least one physical marker at the successive physical tootharrangement with the at least one virtual marker at the successivedigital tooth arrangement using computer-implemented computationalgeometry calculations to verify that the successive physical tootharrangement follows the successive digital tooth arrangement using thecomputing device.
 6. The medium of claim 5, where thecomputer-implemented computational geometry calculations includecomputer-implemented computational geometry calculations to detect aposition of the at least one physical marker on the image.
 7. The mediumof claim 5, where the computer-implemented computational geometrycalculations include computer-implemented computational geometrycalculations to match the at least one physical marker with the virtualtooth model to obtain actual teeth positions.
 8. A system for trackingteeth movement, comprising: a processor; and a memory coupled to theprocessor, wherein the memory includes instructions to: receive avirtual teeth model of physical teeth in an initial tooth arrangementusing a computing device; position at least one virtual marker on atleast one virtual tooth of the virtual teeth model; generate asuccessive digital tooth arrangement for the virtual teeth model usingthe computing device; provide information for positioning at least onephysical marker at a location on at least one of the physical teethcorresponding to a location of the at least one virtual marker on the atleast one virtual tooth; receive an image of the at least one physicalmarker after the physical teeth have moved to a successive physicaltooth arrangement using the computing device; match the at least onephysical marker at the successive physical tooth arrangement with the atleast one virtual marker at the successive digital tooth arrangementusing computer-implemented computational geometry calculations to verifythat the successive physical tooth arrangement follows the successivedigital tooth arrangement using the computing device.
 9. The system ofclaim 8, where the at least one physical marker comprises a pointobject.
 10. The system of claim 9, where the at least one point objectcomprises at least three point objects.
 11. The system of claim 8, wherethe at least one physical marker comprises a number of line objects. 12.The system of claim 8, where the at least one physical marker comprisesa number of point objects and at least one line object.
 13. The methodof claim 8, where the at least one physical marker comprises a number ofshape objects.
 14. The system of claim 8, where the image comprises atleast one X-ray image.
 15. The system of claim 8, where the imagecomprises at least one three dimensional image.
 16. The system of claim8, where the at least one physical marker comprises a colorant.
 17. Thesystem of claim 16, where the colorant comprises a colorant that changescolor when the colorant interacts with a catalyst.
 18. The system ofclaim 8, where at least one physical marker comprises a physical markerformed from a material that is at least temporarily visible within anX-ray spectral range.
 19. The system of claim 8, where at least onephysical marker comprises a physical marker formed from a material thatis at least temporarily visible by an unaided human eye.
 20. The systemof claim 8, where at least one physical marker comprises an applianceattachment to at least one of the physical teeth.